End packing for a deflection compensated roll

ABSTRACT

The present invention relates to an end packing ( 20, 40, 60, 70, 80 ) for a deflection compensated roll. The roll including a stationary shaft ( 1 ) and a roll shell ( 2 ), bearing-mounted rotatably therearound and having each end thereof provided with a shaft-enclosing annular end cap ( 3 ). The end cap ( 3 ) has its surface internal in the axial direction of the roll or its surface external in the axial direction formed with a sealing surface ( 10, 50, 61, 71, 81 ). The end packing elements ( 20, 40, 60, 70, 80 ) are provided with an annular packing member ( 12; 42; 62; 72; 82 ) extending around the shaft ( 2 ) and including a front face, which is directed towards said sealing surface ( 10, 50, 61, 71, 81 ) and which is in contact with the sealing surface ( 10, 50 ) or separated from the sealing surface ( 61, 71, 81 ) by a gap constituting an axially directed narrow slot. The packing member ( 12; 42; 62; 72; 82 ) is provided with elements connected to a supply of compressed air for delivering compressed air into a cavity ( 14, 44, 69, 92, 105 ) between the packing member and the sealing surface, whereby the compressed air striving to flow between the packing member&#39;s front face and the sealing surface into and out of the roll functions as a seal.

FIELD OF THE INVENTION

The present invention relates to an end packing for a deflectioncompensated roll, said roll comprising a stationary shaft and a rollshell, bearing-mounted rotatably therearound and having each end thereofprovided with a shaft-enclosing annular end cap, having its surfaceinternal in the axial direction of the roll or its surface external inthe axial direction formed with a sealing surface, and shaft-mountedbearing elements in each axial end zone of the roll shell inside the endcap. In a second aspect, the invention relates also to an end packingfor a deflection compensated roll, said roll comprising a stationaryshaft and a roll shell bearing-mounted rotatably therearound and havingeach end thereof provided with a shaft-enclosing annular end cap, havingan external surface and an internal surface in the axial direction ofthe roll, said internal surface being formed with a sealing surface, andshaft-mounted bearing elements in each axial end zone of the roll shellinside the end cap, the roll end packing elements being mounted on theshaft in a section between the end cap and the bearing elements for asealing contact against the sealing surface of the end cap. In a thirdaspect, the invention relates also to an end packing for a deflectioncompensated roll, said roll comprising a stationary shaft and a rollshell bearing-mounted rotatably therearound and having each end thereofprovided with a shaft-enclosing annular end cap, having its surfacewhich is internal in the axial direction of the roll formed with asealing surface, and shaft-mounted slide bearing elements in each axialend zone of the roll shell inside the end cap, said slide bearingelements comprising radial slide bearing elements and axial slidebearing elements.

BACKGROUND OF THE INVENTION

FIG. 1 shows one currently available packing system for sealing the endof a roll shell 2 mounted with bearings rotatably around a roll shaft 1.The bearing elements consist of a roller bearing 9. The roll shell hasits axial ends provided with an end cap 3, including projections 6 and 7extending outward in the axial direction of the roll, the innerprojection 7 having its outer surface constitute a sealing surface forpacking elements 8 which are mounted on a body member 4 secured to theshaft 1. The body member 4 is further provided with chute elements 5 forcollecting the oil seeping through the packing. A problem in this systemis that the packing may leak quite easily, i.e. it does not functionproperly as intended. U.S. Pat. No. 6,004,249 discloses an end packingassembly for a roll, comprising a roll shell mounted rotatably around astationary shaft by means of slide bearings. This assembly includesfirst packing elements, comprising a spring-loaded packing member whichis compressible against an internal end cap surface substantiallyperpendicular to the longitudinal axis of the roll shaft. In addition,this assembly includes second packing elements, comprising a chamberprovided on a roll shaft or in an end cap, in which is fitted a radiallymovable ring-shaped packing plate provided with a sealing lip settingagainst a complementary surface. This is a comparatively complexassembly, which is difficult to implement in practice.

OBJECTS AND SUMMARY OF THE INVENTION

Thus, it is an object of the present invention to provide an improvedend packing for a deflection compensated roll, said end packing beingrelatively simple in construction and reliable in operation. In order toaccomplish this object, an end packing of the invention for a deflectioncompensated roll, said roll comprising a stationary shaft and a rollshell bearing-mounted rotatably therearound and having each end thereofprovided with a shaft-enclosing annular end cap, having its surfaceinternal in the axial direction of the roll or its surface external inthe axial direction formed with a sealing surface, and shaft-mountedbearing elements in each axial end zone of the roll shell inside the endcap, is characterized in that the end packing elements are provided withan annular packing member extending around the shaft and comprising afront face, which is directed towards said sealing surface and which isin contact with the sealing surface or separated from the sealingsurface by a gap constituting an axially directed narrow slot, saidpacking member being provided with elements connected to a supply ofcompressed air for delivering compressed air into a cavity between thepacking member and the sealing surface, whereby the compressed airstriving to flow between the packing member's front face and the sealingsurface into and out of the roll functions as a seal.

According to the second aspect of the invention, the invention relatesalso to an end packing for a deflection compensated roll, said rollcomprising a stationary shaft and a roll shell bearing-mounted rotatablytherearound and having each end thereof provided with a shaft-enclosingannular end cap, having an internal surface in the axial direction ofthe roll formed with a sealing surface, and shaft-mounted bearingelements in each axial end zone of the roll shell inside the end cap,the roll end packing elements being mounted on the shaft inside the endcap for a sealing contact against the sealing surface of the end cap,said end packing being characterized in that the packing elementsinclude a labyrinth ring mounted on the shaft, which comprises a packingmember compressible against a sealing surface and provided with sealinglips setting against the sealing surface, between which is a cavityopening towards the sealing surface, and that the labyrinth ring isprovided with a bore, whereby the cavity of the packing member can besupplied with compressed air from a compressed air duct present in theshaft.

According to the third aspect of the invention, the invention relatesalso to an end packing for a deflection compensated roll, said rollcomprising a stationary shaft and a roll shell mounted with bearingsrotatably therearound and having each end thereof provided with ashaft-enclosing annular end cap, having its surface which is internal inthe axial direction of the roll formed with a sealing surface, andshaft-mounted slide bearing elements in the area of each axial end ofthe roll shell inside the end cap, said slide bearing elementscomprising radial slide bearing elements and axial slide bearingelements, whereby the roll end packing elements are mounted inconnection with the shaft inside the end cap for a sealing contactagainst the sealing surface of the end cap, said end packing for aslide-bearing fitted roll being characterized in that the packingelements include a sealing ring linked to the bearing shoes of the axialslide bearing elements and located in radial direction inside saidbearing shoes, said sealing ring being provided with a cavity openingtoward the end cap sealing surface and connected a supply of compressedair, said sealing ring being separated from the end cap sealing surfaceby an axial gap constituting a narrow slot, said slot allowingcompressed air to flow inside the roll and out of the roll.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic side elevation, showing an end packing assembly ofthe prior art described in the introduction.

FIG. 2 is a schematic side elevation, showing one embodiment for an endpacking of the invention in conjunction with a roll shell provided withroller bearings.

FIG. 2A is an enlarged partial view, showing a detail of the packingelements of FIG. 2.

FIG. 3 is a schematic frontal view, showing an end packing componentincluded in the embodiment of FIG. 2.

FIG. 4 is a schematic side elevation, showing a second embodiment for anend packing of the invention in conjunction with a roll shell providedwith slide bearings, and

FIGS. 5-7 show still a few embodiments for an end packing of theinvention in schematic elevations.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 2 and 3, the deflection compensated roll comprises astationary roll shaft 1, and a roll shell 2 bearing-mounted rotatablytherearound with roller bearings 9 and provided with an end cap 3.Viewed in the axial direction of the roll, the end cap includes anexternal surface 19 and an internal surface, said internal surface beingformed with a sealing surface 10. An end packing 20 of the inventioncomprises a labyrinth ring 11 mounted on the roll shaft 1 and formedwith an annular groove 21 opening towards the sealing surface 10 of theend cap 3. The annular groove 21 of the labyrinth ring 11 is providedwith a packing member 12, which has packing lips 22, 23 and an annularcavity 14 therebetween. The packing member 12 has its packing lipscompressed by means of spring loading elements 13 in a sealing fashionagainst the sealing surface 10. The labyrinth ring 11 is mounted on theshaft 1 for example by means of fastening elements, such as bolts,extending through bores 18. The labyrinth ring is preferably mounted onthe same outer diameter section 26 of the shaft 2 as the bearingelements 9. The labyrinth ring 11 is further formed with a bore 15extending in a substantially radial direction of the roll, and with abore 15 a perpendicular thereto and extending in a substantially axialdirection of the roll, said bore 15 a continuing further as a boreextending through the spring loading elements 13 and the packing member12 to the cavity 14. The bore 15 is set in alignment with a bore 16formed in the roll shaft 1 and extending to a substantially axiallydirected air duct 17 normally pre-existing in the roll shaft, wherebythe compressed air supplied into the air duct 17 can be deliveredthrough the bore 16, 15 and 15 a into the cavity 14. The compressed airto be supplied into the cavity 14 has its pressure selected to exceedthe pressure of oil striving to seep through the packing and thus toensure tightness of the packing member 12 against oil leaks in arelatively simple and reliable manner.

In the above embodiment, the end packing 20 is described in connectionwith a roller-bearing mounted roll shell, but it is also adaptable foruse in connection with slide-bearing mounted roll shell, as will bedescribed later with reference to FIG. 4, and also in such a case thatthe roll shell 2 is designed with a stroke, i.e. to be displaceable in aradial direction with respect to the roll shaft 1.

FIG. 4 depicts an end packing 40 in connection with a slide-bearingmounted roll shell. The radially extending slide bearing elements areshown at reference numeral 31 and the axially extending slide bearingelements at reference numeral 30. These are conventional in the art and,hence, not described in more detail in this context. The end packing 40comprises a labyrinth ring 41, which is provided with an annular groove46 opening towards a sealing surface 50 of the end cap 3. The annulargroove 46 is provided with a packing member 42, which has packing lips47, 48 and an annular cavity 44 therebetween, which can be supplied withcompressed air through a bore 45 existing in the roll shaft and a bore45 a present in the packing member 42 and in the labyrinth ring 4.Reference numeral 43 designates a spring element acting on the packingmember 42. The end packing 40 is functionally consistent with the endpacking 20 shown in FIGS. 2 and 3. The main structural difference isthat the labyrinth ring 41 is mounted on another part of the shaft 1,and in the illustrated embodiment the labyrinth ring 41 further includesa bore 49 for axial bearing elements 30.

FIG. 5 depicts an embodiment, wherein the axial bearing elements areprovided with a packing ring 62 which follows a sealing surface 61 ofthe end cap 3 very closely. The ring is made from a material whichconforms as well as possible to resulting deformations and withstands amomentary contact with a rotating end cap. The material can be e.g.bronze for bearings.

The embodiment of FIG. 5 can be implemented e.g. in association with aslide bearing assembly of FIG. 4, the end packing elements 40 of FIG. 4being replaced by the packing ring 62 of FIG. 5, which is mounted on thebearing shoe/shoes of the axial bearing 30 functionally in such a waythat the packing ring 62 is separated from the sealing surface 61 of theend cap 3 by a gap that constitutes a narrow slot 69, thus travelingalong with the bearing shoe/shoes in the axial direction of the roll.The slot 69 is supplied with compressed air through a cavity 63 formedin the packing ring and opening towards the sealing surface 61 of theend cap, said cavity being connected to a supply of compressed air (notshown). The slot 69 allows a flow of compressed air into the roll (anarrow 67) and out of the roll (an arrow 68). The air going into the rolldisplaces the oil striving to get out of the roll. As the roll isrotating, a centrifugal force also strives to hold the oil inside theroll. In addition, the compressed air flowing into the roll is used tomaintain an excess pressure necessary for intensified oil removal. Asfor the mutually opposite faces of the end cap sealing surface 61 andthe packing ring 62, one of said faces is preferably formed withpressure equalizing grooves 64 for ensuring a consistent air flow fromthe entire periphery. The grooves are circumferential and are located inpositions outward from the cavity 63 as seen in radial direction. Inaddition, the compressed air flowing outwards from the roll (the arrow68) strives to keep dirt particles outside, which would otherwise tendto penetrate into the roll.

The end cap has preferably its sealing surface 61 further provided witha circumferential sealing groove 65, which is fitted with a lip seal 66.The lip of the seal 66 disengages as a result of centrifugal force fromits complementary surface as the roll is rotating at a speed requiredfor a high web speed. The axial lip seal provides yet another throttlepoint for compressed air and it functions also as a safety elementwhenever the supply of compressed air disappears for some reason.

FIG. 6 depicts still another embodiment of the invention in connectionwith a slide-bearing mounted roll. Mounting with slide bearings is priorknown for a person skilled in the art and, with regard to a slidebearing assembly, FIG. 6 only illustrates an axially directed slidebearing element 30, which is supplied with a necessary oil pressurealong a channel 104. The end cap 3 of the shell 2 has its internalsurface formed with a sealing surface 71 and the shaft 1 is providedwith a bore, in which an end packing 70 is accommodated. The end packing70 comprises a packing member 72, which is formed with a cavity 79opening in a direction opposite to the sealing surface 71 and connectedto a supply of compressed air (not shown) by way of a channel 102. Thepacking member 72 is formed with bores 73 and 74 for deliveringcompressed air from the cavity 79 into a slot 105 formed between thesealing-surface 71 facing front of the packing member 72 and the sealingsurface 71. The packing member 72 has its front face preferably designedin such a way that the slot 105 is divergent in a direction extendingfrom the bore 73 towards the interior of the roll (an arrow 78). Theslot 105 is preferably about 0.02 mm at the bore 73 and divergesuniformly to a value of about 0.2 mm at its edge leading into the roll.These values are just directive in nature. In the illustratedembodiment, the bore 74 opens into a cavity, this in turn opens towardsthe sealing surface and enhances a uniform distribution of compressedair in circumferential direction. An arrow 77 is used to indicate thedirection of compressed air flowing outwards from the roll. At referencenumeral 100 there is shown a chute element mounted on the shaft 1, whichfunctions as a safety element for collecting the oil possibly seepingthrough the packing.

FIG. 7 shows yet another embodiment of the invention, which is differentfrom that of FIG. 6 in that the end cap has a sealing surface 81 in itsaxially directed external surface. A packing member 82 is accommodatedin a bore, which is formed in a packing body 89 mounted on the shaft 1and which is connected to a supply of compressed air by way of a channel84. A cavity 83 is connected by way of bores 85 and 86 to a slot 92between the packing member 82 and the sealing surface 81. Referencenumeral 91 designate seals.

In the embodiments of FIGS. 5-7, the material of a packing ring ispreferably bronze.

We claim:
 1. An end packing (20, 40, 60, 70, 80) for a deflectioncompensated roll, comprising a stationary shaft (1) and a roll shell(2), bearing-mounted rotatably therearound and having each end thereofprovided with a shaft-enclosing annular end cap (3), having its surfaceinternal in the axial direction of the roll or its surface external inthe axial direction formed with a sealing surface (10, 50, 61, 71, 81),and shaft-mounted bearing elements (9, 30, 31) in each axial end zone ofthe roll shell (2) inside the end cap (3), wherein said end packing (20,40, 60, 70, 80) comprises: an annular packing member (12; 42; 62; 72;82) extending around the shaft (2) and comprising a front face, which isdirected towards said sealing surface (10, 50, 61, 71, 81), said packingmember (12; 42; 62; 72; 82) being provided with elements connected to asupply of compressed air for delivering compressed air into a cavity(14, 44, 69, 92, 105) between the packing member and the sealingsurface, whereby the compressed air striving to flow between the packingmember's front face and the sealing surface into and out of the rollfunctions as a seal.
 2. An end packing (20; 40) for a deflectioncompensated roll, comprising a stationary shaft (1) and a roll shell (2)bearing-mounted rotatably therearound and having each end thereofprovided with a shaft-enclosing annular end cap (3), having an internalsurface in the axial direction of the roll formed with a sealing surface(10; 50), and shaft-mounted bearing elements (9; 30, 31) in each axialend zone of the roll shell (2) inside the end cap (3), the roll endpacking elements (20; 40) being mounted on the shaft (2) inside the endcap (3) for a sealing contact against the sealing surface (10; 50) ofthe end cap, said end packing (20; 40) comprising: a labyrinth ring (11;41) mounted on the shaft (2) and including a packing member (12; 42)which is compressible against the sealing surface (10; 50) and providedwith packing lips (22, 23; 47, 48) setting against the sealing surface(10; 50) and having therebetween a cavity (14; 44) opening towards thesealing surface (10; 50), and that the labyrinth ring (11; 41) isprovided with a bore (15, 15 a; 45 a) for delivering compressed air froma compressed air duct (16, 17; 45) existing in the shaft (2) into thecavity (14; 44) of the packing member (12; 42).
 3. The end packing (20;40) as set forth in claim 2, wherein the packing member (12; 42) isaccommodated in an annular groove (21; 46) formed in the labyrinth ring(11; 41), the space between a bottom (24) of said groove and a bottomsurface (25) of the packing member (12; 42), directed towards the same,being provided with spring loading elements (13; 43) for pressing thepacking member (12; 42) against the sealing surface (10; 50).
 4. The endpacking (20; 40) as set forth in claim 3, wherein the labyrinth ring(11; 41) has its bore (15 a; 45 a) continuing as a bore extendingthrough the spring loading elements (13; 43) and the packing member (12;42).
 5. An end packing (60) for a deflection compensated roll,comprising a stationary shaft and a roll shell bearing-mounted rotatablytherearound and having each end thereof provided with a shaft-enclosingannular end cap (3), having its surface which is internal in the axialdirection of the roll formed with a sealing surface (61), andshaft-mounted slide bearing elements (30, 31) in each axial end zone ofthe roll shell inside the end cap (3), said slide bearing elementscomprising radial slide bearing elements (31) and axial slide bearingelements (30), said end packing (60) comprising: a packing ring (62),coupled functionally with the bearing shoes of the axial slide bearingelements and located, as seen in the radial direction, inside saidbearing shoes, said packing ring being provided with a cavity (63)opening towards the sealing surface (61) of the end cap and connected toa supply of compressed air, said packing ring (62) being separated fromthe sealing surface of the end cap by an axial gap constituting a narrowslot (69), said slot (69) allowing a flow of compressed air into theroll (an arrow 67) and out of the roll (an arrow 68).
 6. The end packingas set forth in claim 5, wherein the packing ring (62) has a front andthe end cap sealing surface (61) has a front face opposite the frontface of said packing ring (62), one of said front faces being formedwith pressure equalizing grooves (64).
 7. The end packing as set forthin claim 5, wherein the end cap has its sealing surface (61) furtherprovided with a sealing groove (65), which is fitted with a lip seal(66) subjected to an axially directed loading towards the packing ring(62).